1. Field of the Invention
The present invention relates to a cross-connection apparatus for B-ISDN (Broadband-Integrated Service Digital Network), more particularly, it relates to a cross-connection apparatus having a monitor function using a monitor cell which is inserted therein and extracted therefrom.
2. Description of the Related Art
Recently, B-ISDN has been developed and widely utilized as a high speed and broadband information processing network enabling, so-called, multi media service. In general, a fixed length packet is used to transfer the information in this type of network. Further, an ATM (Asynchronous Transfer Mode) network has been developed as a technique easily realizing a B-ISDN. In the ATM network, ATM cells are used as the above fixed length packets rather than STM (Synchronous Transfer Mode) method, because the ATM cells are suitable for the control of a distributed processing since it is not necessary to perform an allocation of time slots when transferring information. Accordingly, the ATM network can easily realize the multi media service.
In this case, it is necessary to monitor an operation of the cross-connection apparatus to determine whether or not it is operating normally. Accordingly, a monitor cell is used for the above. An OAM (Operation, Administration and Maintenance) cell is used as the monitor cell in the B-ISDN as explained in detail below.